Touch panel and display device using the same

ABSTRACT

An exemplary touch panel includes a first electrode plate and a second electrode plate separated from the first electrode plate. The first electrode plate includes a first substrate and a first conductive layer disposed on a lower surface of the first substrate. The second electrode plate includes a second substrate and a second conductive layer disposed on an upper surface of the second substrate. Each of the first conductive layer and the second conductive layer includes a plurality of spaced carbon nanotube structures. A display device incorporates the touch panel and also includes a display element adjacent to the touch panel.

RELATED APPLICATIONS

This application is related to commonly-assigned applications Ser. No.12/286,266, entitled, “TOUCH PANEL”, filed on Sep. 29, 2008, Ser. No.12/286,141, entitled, “TOUCH PANEL”, filed on Sep. 29, 2008, Ser. No.12/286,189, entitled, “TOUCH PANEL AND DISPLAY DEVICE USING THE SAME”,filed on Sep. 29, 2008, Ser. No. 12/286,181, entitled, “TOUCH PANEL ANDDISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008, Ser. No.12/286,176, entitled, “TOUCH PANEL AND DISPLAY DEVICE USING THE SAME”,filed on Sep. 29, 2008, Ser. No. 12/286,166, entitled, “TOUCH PANEL ANDDISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008, Ser. No.12/286,178, entitled, “TOUCH PANEL AND DISPLAY DEVICE USING THE SAME”,filed on Sep. 29, 2008, Ser. No. 12/286,148, entitled, “TOUCH PANEL ANDDISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008, Ser. No.12/286,140, entitled, “TOUCHABLE CONTROL DEVICE”, filed on Sep. 29,2008, Ser. No. 12/286,154, entitled, “TOUCH PANEL AND DISPLAY DEVICEUSING THE SAME”, filed on Sep. 29, 2008, Ser. No. 12/286,216, entitled,“TOUCH PANEL AND DISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008,Ser. No. 12/286,152, entitled, “TOUCH PANEL AND DISPLAY DEVICE USING THESAME”, filed on Sep. 29, 2008, Ser. No. 12/286,145, entitled, “TOUCHPANEL AND DISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008, Ser.No. 12/286,155, entitled, “TOUCH PANEL, METHOD FOR MAKING THE SAME, ANDDISPLAY DEVICE ADOPTING THE SAME”, filed on Sep. 29, 2008, Ser. No.12/286,146, entitled, “TOUCH PANEL AND DISPLAY DEVICE USING THE SAME”,filed on Sep. 29, 2008, Ser. No. 12/286,228, entitled, “TOUCH PANEL,METHOD FOR MAKING THE SAME, AND DISPLAY DEVICE ADOPTING THE SAME”, filedon Sep. 29, 2008, Ser. No. 12/286,153, entitled, “TOUCH PANEL ANDDISPLAY DEVICE USING THE SAME”, filed Ser. No. 12/286,184, entitled,“TOUCH PANEL AND DISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008,Ser. No. 12/286,175, entitled, “METHOD FOR MAKING TOUCH PANEL”, filed onSep. 29, 2008, Ser. No. 12/286,195, entitled, “METHOD FOR MAKING TOUCHPANEL”, filed on Sep. 29, 2008, Ser. No. 12/286,160, entitled. “TOUCHPANEL AND DISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008, Ser.No. 12/286,220, entitled, “TOUCH PANEL AND DISPLAY DEVICE USING THESAME”, filed on Sep. 29, 2008, Ser. No. 12/286,227, entitled, “TOUCHPANEL AND DISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008, Ser.No. 12/286,144, entitled, “TOUCH PANEL AND DISPLAY DEVICE USING THESAME”, filed on Sep. 29, 2008, Ser. No. 12/286,218, entitled, “TOUCHPANEL AND DISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008, Ser.No. 12/286,142, entitled, “TOUCH PANEL AND DISPLAY DEVICE USING THESAME”, filed on Sep. 29, 2008, Ser. No. 12/286,241, entitled, “TOUCHPANEL AND DISPLAY DEVICE USING THE SAME”, filed on Sep. 29, 2008, Ser.No. 12/286,151, entitled, “TOUCH PANEL, METHOD FOR MAKING THE SAME, ANDDISPLAY DEVICE ADOPTING THE SAME”, filed on Sep. 29, 2008, Ser. No.12/286,143, entitled, “ELECTRONIC ELEMENT HAVING CARBON NANOTUBES”,filed on Sep. 29, 2008, and Ser. No. 12/286,219, entitled, “TOUCH PANEL,METHOD FOR MAKING THE SAME, AND DISPLAY DEVICE ADOPTING THE SAME”, filedon Sep. 29, 2008. The disclosures of the above-identified applicationsare incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to a carbon nanotube based touch panel anda display device incorporating the same.

2. Discussion of Related Art

Following the advancement in recent years of various electronicapparatuses, such as mobile phones, car navigation systems and the like,toward high performance and diversification, there has been continuousgrowth in the number of electronic apparatuses equipped with opticallytransparent touch panels at the front of their respective displaydevices (e.g., liquid crystal panels). A user of any such electronicapparatus operates it by pressing or touching the touch panel with afinger, a pen, a stylus, or a like tool while visually observing thedisplay device through the touch panel. Therefore, a demand exists fortouch panels that are superior in visibility and reliable in operation.

At present, different types of touch panels, including resistance,capacitance, infrared, and surface sound-wave types have been developed.Due to their high accuracy and low cost of production, resistance-typetouch panels have been widely used. A conventional resistance-type touchpanel includes an upper substrate, a transparent upper conductive layerformed on a lower surface of the upper substrate, a lower substrate, atransparent lower conductive layer formed on an upper surface of thelower substrate, and a plurality of dot spacers formed between thetransparent upper conductive layer and the transparent lower conductivelayer. The transparent upper conductive layer and the transparent lowerconductive layer are formed of electrically conductive indium tin oxide(ITO).

In operation, an upper surface of the upper substrate is pressed with afinger, a pen, or a like tool, and visual observation of a screen on theliquid crystal display device provided on a back side of the touch panelis provided. This causes the upper substrate to be deformed, and theupper conductive layer thus comes in contact with the lower conductivelayer at the position where the pressing occurs. Voltages are separatelyapplied by an electronic circuit to the transparent upper conductivelayer and the transparent lower conductive layer. Thus, the deformedposition can be detected by the electronic circuit.

Each of the transparent conductive layers (e.g., ITO layers) isgenerally formed by means of ion-beam sputtering, and this method isrelatively complicated. Additionally, the ITO layer has poorwearability/durability, low chemical endurance, and uneven resistanceover an entire area of the touch panel. Furthermore, the ITO layer hasrelatively low transparency. All the above-mentioned problems of the ITOlayer make for a touch panel with low sensitivity, accuracy, andbrightness.

What is needed, therefore, is to provide a durable touch panel and adisplay device using the same with high sensitivity, accuracy, andbrightness.

SUMMARY

In one embodiment, a touch panel includes a first electrode plate and asecond electrode plate separated from the first electrode plate. Thefirst electrode plate includes a first substrate and a first conductivelayer disposed on a lower surface of the first substrate. The secondelectrode plate includes a second substrate and a second conductivelayer disposed on an upper surface of the second substrate. At least oneof the first conductive layer and the second conductive layer includes aplurality of spaced carbon nanotube structures. A display deviceincorporates the touch panel and also includes a display elementadjacent to the touch panel.

Other advantages and novel features of the present touch panel anddisplay device using the same will become more apparent from thefollowing detailed description of exemplary embodiments when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present touch panel and display device using thesame can be better understood with reference to the following drawings.The components in the drawings are not necessarily to scale, theemphasis instead being placed upon clearly illustrating the principlesof the present touch panel and display device using the same.

FIG. 1 is an exploded, isometric view of a touch panel in accordancewith a present embodiment, showing a first substrate thereof inverted.

FIG. 2 is a transverse, cross-sectional view of the touch panel of FIG.1 once assembled.

FIG. 3 shows a Scanning Electron Microscope (SEM) image of a carbonnanotube film used in the touch panel of FIG. 1.

FIG. 4 is a structural schematic of a carbon nanotube segment.

FIG. 5 is essentially a schematic cross-sectional view of the touchpanel of the present embodiment used with a display element of a displaydevice, showing operation of the touch panel with a touch tool.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate at least one embodiment of the present touch panel anddisplay device using the same, in at least one form, and suchexemplifications are not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Reference will now be made to the drawings to describe, in detail,embodiments of the present touch panel and display device using thesame.

Referring to FIG. 1 and FIG. 2, a touch panel 10 includes a firstelectrode plate 12, a second electrode plate 14, and a plurality of dotspacers 16 disposed between the first electrode plate 12 and the secondelectrode plate 14. The first electrode plate 12 includes a firstsubstrate 120, a first conductive layer 122, and two first-electrodes124. The first substrate 120 includes an upper surface and a lowersurface, each of which is substantially flat. The two first-electrodes124 and the first conductive layer 122 are disposed on the lower surfaceof the first substrate 120. The two first-electrodes 124 are disposedseparately on opposite ends of the first conductive layer 122. Adirection from one of the first-electrodes 124 across the firstconductive layer 122 to the other first-electrode 124 is defined as afirst direction. The two first-electrodes 124 are electrically connectedwith the first conductive layer 122.

The second electrode plate 14 includes a second substrate 140, a secondconductive layer 142, and two second-electrodes 144. The secondsubstrate 140 includes an upper surface and a lower surface, each ofwhich is substantially flat. The two second-electrodes 144 and thesecond conductive layer 142 are disposed on the upper surface of thesecond substrate 140. The two second-electrodes 144 are disposedseparately on opposite ends of the second conductive layer 142. Adirection from one of the second-electrodes 144 across the secondconductive layer 142 to the other second-electrode 144 is defined as asecond direction. The two second-electrodes 144 are electricallyconnected with the second conductive layer 142.

The first direction is perpendicular to the second direction. That is,the two first-electrodes 124 are aligned parallel to the seconddirection, and the two second-electrodes 144 aligned parallel to thefirst direction. The first substrate 120 is a transparent and flexiblefilm/plate. The second substrate 140 is a transparent plate. Thefirst-electrodes 124 and the second-electrodes 144 are made of metal orany other suitable conductive material. In the present embodiment, thefirst substrate 120 is a polyester film, the second substrate 140 is aglass plate, and the first-electrodes 124 and second-electrodes 144 aremade of a conductive silver paste.

An insulative layer 18 is provided between the first and the secondelectrode plates 12 and 14. The first electrode plate 12 is located onthe insulative layer 18. The first conductive layer 122 is opposite to,but is spaced from, the second conductive layer 142. The dot spacers 16are separately located on the second conductive layer 142. A distancebetween the second electrode plate 14 and the first electrode plate 12is in an approximate range from 2 to 20 microns. The insulative layer 18and the dot spacers 16 are made of, for example, insulative resin or anyother suitable insulative material. Insulation between the firstelectrode plate 12 and the second electrode plate 14 is provided by theinsulative layer 18 and the dot spacers 16. It is to be understood thatthe dot spacers 16 are optional, particularly when the touch panel 10 isrelatively small. They serve as supports given the size of the span andthe strength of the first electrode plate 12.

In the present embodiment, a transparent protective film 126 is disposedon the upper surface of the first electrode plate 12. The material ofthe transparent protective film 126 can be selected from a groupconsisting of silicon nitrides, silicon dioxides, benzocyclobutenes,polyester films, and polyethylene terephthalates. The transparentprotective film 126 can be made of slick plastic and receive a surfacehardening treatment to protect the first electrode plate 12 from beingscratched when in use.

At least one of the first conductive layer 122 and the second conductivelayer 142 includes a plurality of spaced carbon nanotube structures. Thecarbon nanotube structures can be parallel to each other. The carbonnanotube structure can have a strip shaped film structure (i.e., carbonnanotube strip-shaped film structure). Each carbon nanotube structurecan be a carbon nanotube film formed of a plurality of carbon nanotubesaligned parallel to a same direction (i.e., collinear and/or parallel).Each carbon nanotube structure can instead be a plurality of stackedcarbon nanotube films, with adjacent carbon nanotube films held togetherby van der Waals attractive force therebetween. The carbon nanotubes ineach carbon nanotube film are arranged parallel to a same direction.Carbon nanotubes of any two adjacent carbon nanotube films are arrangedalong a same direction or different directions. In one embodiment, thecarbon nanotube structures are parallel with each other. In anotherembodiment, the carbon nanotube structures are not parallel with eachother.

Referring to FIGS. 3 and 4, each carbon nanotube film comprises aplurality of successively oriented carbon nanotube segments 143 joinedend-to-end by van der Waals attractive force therebetween. Each carbonnanotube segment 143 includes a plurality of carbon nanotubes 145parallel to each other, and combined by van der Waals attractive forcetherebetween. Lengths and widths of the carbon nanotube films can be setas desired. A thickness of each carbon nanotube film is in anapproximate range from 0.5 nanometers to 100 micrometers. A width of thecarbon nanotube film is typically in an approximate range from 100micrometers to 10 centimeters. A distance between adjacent carbonnanotube films (on either or both of the first conductive layer 122 andthe second conductive layer 142) is in an approximate range from 5nanometers to 1 millimeter.

In the present embodiment, the first conductive layer 122 and the secondconductive layer 142 both include a plurality of spaced carbon nanotubestructures. The carbon nanotube structure is a carbon nanotubestrip-shaped film structure. Each carbon nanotube strip-shaped filmstructure includes at least one carbon nanotube film, and each carbonnanotube film includes a plurality of successive and oriented carbonnanotube segments 143 joined end to end by the van der Waals attractiveforce therebetween. The carbon nanotube strip-shaped film structures ofthe first conductive layer 122 cross the carbon nanotube strip-shapedfilm structures of the second conductive layer 142. That is, the carbonnanotube strip-shaped film structures of the first conductive layer 122are aligned along the first direction, and the carbon nanotubestrip-shaped film structures of the second conductive layer 142 arealigned along the second direction. In this embodiment, the firstdirection is perpendicular to the second direction. In otherembodiments, the first direction can be non-perpendicular (oblique) tothe second direction.

A method for fabricating the above-described first conductive layer 122and second conductive layer 142 includes the steps of: (a) providing anarray of carbon nanotubes, specifically, providing a super-aligned arrayof carbon nanotubes; (b) pulling out a carbon nanotube film from thearray of carbon nanotubes, by using a tool (e.g., adhesive tape, pliers,tweezers, or another tool allowing multiple carbon nanotubes to begripped and pulled simultaneously), thereby obtaining at least onecarbon nanotube strip-shaped film structure; and (c) placing a pluralityof the carbon nanotube strip-shaped film structures thus formed inparallel and spaced apart from each other on each of the first substrate120 and the second substrate 140, thereby forming a first conductivelayer 122 on the first substrate 120 and a second conductive layer 142on the second substrate 140.

In step (a), a given super-aligned array of carbon nanotubes can beformed by the substeps of: (a1) providing a substantially flat andsmooth substrate; (a2) forming a catalyst layer on the substrate; (a3)annealing the substrate with the catalyst layer in air at a temperaturein an approximate range from 700° C. to 900° C. for about 30 to 90minutes; (a4) heating the substrate with the catalyst layer to atemperature in the approximate range from 500° C. to 740° C. in afurnace with a protective gas therein; and (a5) supplying a carbonsource gas to the furnace for about 5 to 30 minutes and growing thesuper-aligned array of carbon nanotubes on the substrate.

In step (a1), the substrate can be a P-type silicon wafer, an N-typesilicon wafer, or a silicon wafer with a film of silicon dioxidethereon. A 4-inch P-type silicon wafer is used as the substrate in thepresent embodiment.

In step (a2), the catalyst can be made of iron (Fe), cobalt (Co), nickel(Ni), or any alloy thereof.

In step (a4), the protective gas can be made up of at least one ofnitrogen (N₂), ammonia (NH₃), and a noble gas. In step (a5), the carbonsource gas can be a hydrocarbon gas, such as ethylene (C₂H₄), methane(CH₄), acetylene (C₂H₂), ethane (C₂H₆), or any combination thereof.

The super-aligned array of carbon nanotubes can, opportunely, have aheight of about 50 microns to 5 millimeters and include a plurality ofcarbon nanotubes 145 parallel to each other and approximatelyperpendicular to the substrate. The carbon nanotubes 145 in the array ofcarbon nanotubes can be multi-walled carbon nanotubes, double-walledcarbon nanotubes or single-walled carbon nanotubes. Diameters of thesingle-walled carbon nanotubes approximately range from 0.5 to 50nanometers. Diameters of the double-walled carbon nanotubesapproximately range from 1 to 50 nanometers. Diameters of themulti-walled carbon nanotubes approximately range from 1.5 to 50nanometers.

The super-aligned array of carbon nanotubes formed under the aboveconditions is essentially free of impurities such as carbonaceous orresidual catalyst particles. The carbon nanotubes 145 in thesuper-aligned array are closely packed together by van der Waalsattractive force therebetween.

In step (b), the carbon nanotube film can be formed by the substeps of:(b1) selecting one or more carbon nanotubes having a predetermined widthfrom the array of carbon nanotubes; and (b2) pulling the carbonnanotubes to form nanotube segments 143 at an even/uniform speed toachieve a uniform carbon nanotube film.

In step (b1), the carbon nanotube segment 143 includes a plurality ofcarbon nanotubes 145 parallel to each other. The carbon nanotubesegments 143 can be selected by using an adhesive tape as the tool tocontact the super-aligned array of carbon nanotubes. In step (b2), thepulling direction is substantially perpendicular to the growingdirection of the super-aligned array of carbon nanotubes. Morespecifically, during the pulling process, as the initial carbon nanotubesegments 143 are drawn out, other carbon nanotube segments 143 are alsodrawn out end to end due to van der Waals attractive force between endsof adjacent carbon nanotube segments 143. This process of drawingensures a substantially continuous and uniform carbon nanotube film canbe formed.

The carbon nanotube film includes a plurality of carbon nanotubesegments 143. The carbon nanotubes 145 in the carbon nanotube film areall substantially parallel to the pulling/drawing direction of thecarbon nanotube film, and the carbon nanotube film produced in suchmanner can be selectively formed having a predetermined width. Thecarbon nanotube film formed by the pulling/drawing method has superioruniformity of thickness and conductivity over a disordered carbonnanotube film. Further, the pulling/drawing method is simple, fast, andsuitable for industrial applications.

In the present embodiment, each carbon nanotube strip-shaped filmstructure includes a single carbon nanotube film. Each carbon nanotubefilm comprises a plurality of carbon nanotube segments 143 which are inturn comprised of a plurality of carbon nanotubes 145 arranged along asame direction. The direction is generally the pulling direction. Assuch, at least two carbon nanotube films are arranged on top of oneanother, and the nanotubes are arranged along a same orientation. Thecarbon nanotubes in the carbon nanotube film are arranged along adirection extending from one of the two first or second electrodes 142,144 to the other first or second electrodes 142, 144.

The width of the carbon nanotube film depends on a size of the carbonnanotube array. The length of the carbon nanotube film can be set, asdesired. In one useful embodiment, when the substrate is a 4 inch typewafer as in the present embodiment, the width of the carbon nanotubefilm is in an approximate range from 0.5 nanometers to 10 centimeters,and the thickness of the carbon nanotube film is in the approximaterange from 0.5 nanometers to 100 micrometers. The carbon nanotubes inthe carbon nanotube film can be selected from a group consisting ofsingle-walled carbon nanotubes, double-walled carbon nanotubes, andmulti-layer carbon nanotubes. Diameters of the single-walled carbonnanotubes approximately range from 0.5 to 50 nanometers. Diameters ofthe double-walled carbon nanotubes approximately range from 1 to 50nanometers. Diameters of the multi-walled carbon nanotubes approximatelyrange from 1.5 to 50 nanometers.

When the size of the carbon nanotube film is large, step (b) can furtherinclude cutting the carbon nanotube film into a plurality of smallersized carbon nanotube films, thereby obtaining a plurality of carbonnanotube strip-shaped film structures.

It is noted that because the carbon nanotubes in the super-alignedcarbon nanotube array have a high purity and a high specific surfacearea, the carbon nanotube film is adherent in nature. As such, eachcarbon nanotube strip-shaped film structure can be adhered directly to asurface of the first substrate 120, the second substrate 140, and/oranother carbon nanotube strip-shaped film structure without the use ofan adhesive.

In step (c), each carbon nanotube strip-shaped film structure can be acarbon nanotube film or a plurality of carbon nanotube films stacked oneon the other. When the carbon nanotube strip-shaped film structure is aplurality of stacked carbon nanotube films, the carbon nanotubes in eachtwo adjacent carbon nanotube films are arranged along a same directionor different directions. In each of the first and second conductivelayers 122, 142, distances between adjacent carbon nanotube strip-shapedfilm structures are in an approximate range from 5 nanometers to 1millimeter. The distances can be configured according to the desiredoptical transparency properties of the touch panel 10. Further, in thepresent embodiment, all the adjacent carbon nanotube strip-shaped filmstructures are spaced apart a same distance.

The carbon nanotube strip-shaped film structures, once adhered to asurface of the first substrate 120 or the second substrate 140 can betreated with an organic solvent. The carbon nanotube strip-shaped filmstructures can be treated by using organic solvent to soak the entiresurface of the carbon nanotube film. The organic solvent isvolatilizable and can, suitably, be selected from the group consistingof ethanol, methanol, acetone, dichloroethane, chloroform, andcombinations thereof. In the present embodiment, the organic solvent isethanol. After being soaked by the organic solvent, microscopically,carbon nanotube strings will be formed by adjacent carbon nanotubes inthe carbon nanotube strip-shaped film structures, that are able to doso, bundling together, due to the surface tension of the organicsolvent. In one aspect, part of the carbon nanotubes in the untreatedcarbon nanotube strip-shaped film structures that are not adhered on thesubstrate will adhere on the substrate 120,140 after the organic solventtreatment due to the surface tension of the organic solvent. Then thecontacting area of the carbon nanotube strip-shaped film structures withthe substrate will increase, and thus, the carbon nanotube strip-shapedfilm structures can more firmly adhere to the surface of the firstsubstrate 120,140. In another aspect, due to the decrease of thespecific surface area via bundling, the mechanical strength andtoughness of the carbon nanotube strip-shaped film structures areincreased and the coefficient of friction of the carbon nanotubestrip-shaped film structures is reduced. Macroscopically, thestrip-shaped film structures will be an approximately uniform carbonnanotube film.

In step (c), the two ends of the carbon nanotube structures of the firstconductive layer 122 are connected to the two first-electrodes 124, andthe two ends of the carbon nanotube structures of the second conductivelayer 142 are connected to the two second-electrodes 144. The alignmentdirection of the carbon nanotube structures in the first conductivelayer 122 can be different from the first direction. In the illustratedembodiment, the carbon nanotube structures in the first conductive layer122 are arranged along the first direction, and are spaced apart fromeach other a certain distance. The alignment direction of the carbonnanotube structures in the second conductive layer 142 can be differentfrom the second direction. In the illustrated embodiment, the carbonnanotube structures in the second conductive layer 142 are arrangedalong the second direction, and are spaced apart from each other acertain distance. The first direction is perpendicular to the seconddirection. The first-electrodes 124 and the second-electrodes 144 arestrip-shaped structures.

On each of the first conductive layer 122 and the second conductivelayer 142, air gaps exist between the adjacent, parallel carbon nanotubestructures. Furthermore, the optical refractive index and the opticaltransmission rate of the carbon nanotube structures are different fromthose of air. Accordingly, a filling layer (not labeled) with almost thesame optical refractive index and almost the same optical transmissionrate of the carbon nanotube structure can be formed in the gap betweenthe adjacent carbon nanotube structures.

The touch panel 10 can further include a shielding layer (not shown)disposed on the lower surface of the second substrate 140. The materialof the shielding layer can be selected from indium tin oxides, antimonytin oxides, carbon nanotube films, and other suitable conductivematerials. In the present embodiment, the shielding layer is a carbonnanotube film. The carbon nanotube film includes a plurality of carbonnanotubes, and the orientations of the carbon nanotubes therein can bearbitrary. The carbon nanotubes in the carbon nanotube film of theshielding layer are arranged along a same direction. The carbon nanotubefilm is connected to ground and acts as a shield, thus enabling thetouch panel 10 to operate without interference (e.g., electromagneticinterference).

Referring to FIG. 5, a display device 100 includes the touch panel 10, adisplay element 20, a first controller 30, a central processing unit(CPU) 40, and a second controller 50. The touch panel 10 is opposite andadjacent to the display element 20, and is connected to the firstcontroller 30 by an external circuit. The touch panel 10 can be spacedfrom the display element 20 or installed directly on the display element20. In the illustrated embodiment, the touch panel 10 is spaced from thedisplay element 20, with a gap 26. The first controller 30, the CPU 40,and the second controller 50 are electrically connected. The CPU 40 isconnected to the second controller 50 to control the display element 20.

The display element 20 can be, e.g., a liquid crystal display, a fieldemission display, a plasma display, an electroluminescent display, avacuum fluorescent display, a cathode ray tube, or another displaydevice.

When a shielding layer 22 is disposed on the lower surface of the secondsubstrate 140, a passivation layer 24 is disposed on a surface of theshielding layer that faces away from the second substrate 140. Thematerial of the passivation layer 24 can, for example, be siliconnitride or silicon dioxide. The passivation layer 24 can be spaced fromthe display element 20 a certain distance or can be installed on thedisplay element 20. The passivation layer 24 can protect the shieldinglayer 22 from chemical or mechanical damage.

In operation, 5V are applied to each of the two first-electrodes 124 ofthe first electrode plate 12 and to each of the two second-electrodes144 of the second electrode plate 14. A user operates the display bypressing the first electrode plate 12 of the touch panel 10 with afinger, a pen/stylus 60, or the like while visually observing thedisplay element 20 through the touch panel 10. This pressing causes adeformation 70 of the first electrode plate 12. The deformation 70 ofthe first electrode plate 12 causes a connection between the firstconductive layer 122 and the second conduction layer 142 of the secondelectrode plate 14. Changes in voltages in the first direction of thefirst conductive layer 142 and the second direction of the secondconductive layer 142 can be detected by the first controller 30. Thenthe first controller 30 transforms the changes in voltages intocoordinates of the pressing point, and sends the coordinates of thepressing point to the CPU 40. The CPU 40 then sends out commandsaccording to the coordinates of the pressing point and further controlsthe display of the display element 20.

The properties of the carbon nanotubes provide superior toughness, highmechanical strength, and uniform conductivity to each carbon nanotubefilm and the corresponding carbon nanotube structure. Thus, the touchpanel 10 and the display device 100 adopting the carbon nanotubestructures in the conductive layers are durable and highly conductive.Furthermore, since the carbon nanotubes have excellent electricalconductivity properties, each of the first and second conductive layers122, 142 formed by a plurality of carbon nanotube structures parallel toeach other and spaced apart from each other has uniform resistancedistribution. Thus the touch panel 10 and the display device 100 haveimproved sensitivity and accuracy.

Finally, it is to be understood that the above-described embodiments areintended to illustrate rather than limit the invention. Variations maybe made to the embodiments without departing from the spirit of theinvention as claimed. The above-described embodiments illustrate thescope of the invention but do not restrict the scope of the invention.

1. A touch panel comprising: a first electrode plate comprising a firstsubstrate and a first conductive layer disposed on a lower surface ofthe first substrate; and a second electrode plate separated from thefirst electrode plate and comprising a second substrate and a secondconductive layer disposed on an upper surface of the second substrate;wherein the first conductive layer and the second conductive layer bothcomprise a plurality of carbon nanotube structures spaced and parallelto each other, and a first alignment direction of each of the carbonnanotube structures in the first conductive layer crosses a secondalignment direction of each of the carbon nanotube structures in thesecond conductive layer.
 2. The touch panel as claimed in claim 1,wherein at least one of the carbon nanotube structures comprises atleast one carbon nanotube film comprising a plurality of carbonnanotubes arranged along a same direction.
 3. The touch panel as claimedin claim 2, wherein each carbon nanotube structure comprises at leasttwo carbon nanotube films stacked one on the other, and adjacent carbonnanotube films are combined by van der Waals attractive forcetherebetween.
 4. The touch panel as claimed in claim 3, wherein eachcarbon nanotube film comprises a plurality of successively orientedcarbon nanotube segments joined end to end by van der Waals attractiveforce therebetween.
 5. The touch panel as claimed in claim 1, wherein athickness of each of the carbon nanotube structures is in an approximaterange from 0.5 nanometers to 100 micrometers.
 6. The touch panel asclaimed in claim 1, wherein a width of each carbon nanotube structure isin an approximate range from 100 micrometers to 10 centimeters.
 7. Thetouch panel as claimed in claim 1, wherein a distance between adjacentcarbon nanotube structures is in an approximate range from 5 nanometersto 1 millimeter.
 8. The touch panel as claimed in claim 1, wherein thefirst electrode plate further comprises two first-electrodes, the secondalignment direction is perpendicular to first alignment direction, andeach of the two first-electrodes is oriented along the second alignmentdirection and electrically connected to the first conductive layer. 9.The touch panel as claimed in claim 8, wherein the second electrodeplate further comprises two second-electrodes, and each of the twosecond-electrodes is oriented along the first alignment direction andelectrically connected to the second conductive layer.
 10. The touchpanel as claimed in claim 1, further comprising an insulative layerdisposed between the second electrode plate and the first electrodeplate.
 11. The touch panel as claimed in claim 10, wherein a pluralityof dot spacers are disposed between the first conductive layer of thefirst electrode plate and the second conductive layer of the secondelectrode plate.
 12. The touch panel as claimed in claim 1, furthercomprising a shielding layer disposed on a lower surface of the secondsubstrate of the second electrode plate, material of the shielding layerbeing selected from the group consisting of indium tin oxides, antimonytin oxides, and carbon nanotube films.
 13. A display device comprising:a touch panel comprising a first electrode plate and a second electrodeplate; the first electrode plate comprising a first substrate and afirst conductive layer disposed on a lower surface of the firstsubstrate; the second electrode plate separated from the first electrodeplate and comprising a second substrate and a second conductive layerdisposed on an upper surface of the second substrate; and a displayelement opposite and adjacent to the touch panel; wherein the firstconductive layer and the second conductive layer both comprise aplurality of spaced carbon nanotube structures parallel to each other,and a first alignment direction of each of the carbon nanotubestructures in the first conductive layer crosses a second alignmentdirection of each of the carbon nanotube structures in the secondconductive laver.
 14. The display device as claimed in claim 13, whereinthe touch panel is spaced from the display element with a distance. 15.The display device as claimed in claim 13, wherein the touch panel islocated on the display element.
 16. The display device as claimed inclaim 13, further comprising a passivation layer located on a surface ofthe touch panel, and the material of the passivation layer beingselected from the group consisting of silicon nitride and silicondioxide.
 17. A touch panel comprising: a first electrode platecomprising a first substrate and a first conductive layer disposed on alower surface of the first substrate; and a second electrode plateseparated from the first electrode plate and comprising a secondsubstrate and a second conductive layer disposed on an upper surface ofthe second substrate; wherein at least one of the first conductive layerand second conductive layer comprises a plurality of carbon nanotubestrip-shaped film structures spaced from and parallel with each other,and each of the plurality of carbon nanotube strip-shaped filmstructures comprising a plurality of carbon nanotubes.
 18. The touchpanel as claimed in claim 17, wherein the plurality of carbon nanotubesare arranged along a same direction in each of the plurality of carbonnanotube strip-shaped film structures.
 19. The touch panel as claimed inclaim 18, wherein each of the plurality of carbon nanotube strip-shapedfilm structures comprises a plurality of successively oriented carbonnanotube segments joined end to end by van der Waals attractive forcetherebetween.
 20. The touch panel as claimed in claim 17, wherein thefirst conductive layer and second conductive layer both comprise aplurality of carbon nanotube strip-shaped film structures spaced fromand parallel with each other, and the plurality of carbon nanotubestrip-shaped film structures of the first conductive layer cross theplurality of carbon nanotube strip-shaped film structures of the secondconductive layer.